According to Richard Goldstein, DVM, an associate professor of small animal medicine at Cornell University’s College of Veterinary Medicine, the frequency with which cats routinely move their bowels varies considerably from animal to animal. “Cats typically move their bowels one to three times a day,” he notes, “depending to some extent on the type of food they eat. You should seek veterinary consultation if your cat doesn’t defecate for more than a day or two.” You should be especially concerned, he adds, if the animal seems to be straining in its litter box, crying out in pain as it tries to defecate, or if there is blood in the bits of stool that it has managed to expel.

Prompt veterinary examination is warranted for another most important reason, Dr. Goldstein notes. “Straining in the litter box may be a sign that the cat is harboring a lower urinary tract disease and is unable to urinate properly,” he says, “and that would surely call for emergency care. You have to be certain that the animal is truly constipated and doesn’t have a life-threatening urinary tract obstruction.”

In a constipated cat, the colon—the section of the lower intestine that functions as a reservoir for undigested food, mucus, bacteria, and dead cells prior to evacuation—has become impacted with feces that will not budge. Colonic obstruction can have varying degrees of severity, says Dr. Goldstein. The most common and least severe occurrence is occasional constipation, which is generally treatable with enemas, medication, and dietary adjustment. If left untreated, however, the condition can proceed to obstipation, a more severe and stubborn fecal impaction that may require hospitalization and elaborate therapy, including manual removal of hardened fecal matter from an anesthetized cat’s colon. And some cats may suffer from a condition known as megacolon, in which the colon becomes grossly dilated and unable to function properly. This condition leads to severe constipation and could eventually prove fatal without treatment, which would typically entail surgical removal of part of the colon.

In cases of advanced and untreated constipation, says Dr. Goldstein, “The cat is completely unable to evacuate its bowels. The intestines get stretched to the point at which translocation of bacteria begins. That is, the barrier that normally prevents bacteria from moving from the animal’s feces into its bloodstream is no longer functioning. The cat becomes systemically ill and, if not treated, will die.”

Diagnosing constipation is relatively straightforward. The procedure will typically include baseline blood tests, a blood chemistry analysis, urinalysis, and various tests to rule out a urinary tract infection. Also important is abdominal palpation, in which the veterinarian’s hands probe the abdominal area along the entire length of the colon to see if it is distended with fecal matter. Radiographs will be taken to confirm suspected constipation and show the extent to which the colon is dilated and whether a stricture appears to be present. In some instances, ultrasound imaging may also be used in order to rule out the presence of an obstructive tumor.

If a cat with colonic obstruction is dehydrated, treatment is apt to begin with intravenous fluid therapy. However, says Dr. Goldstein, “The first level of care for mild obstruction will usually involve dietary change—the addition of fiber and other foods that promote colonic motility.” This treatment, along with administration of medications that will make the fecal matter more liquid, can be carried out at home.

If these measures fail to relieve the constipation, the veterinarian is likely to try a warm-water enema, repeating the process as often as necessary to produce results. (Owners should never attempt this at home, advises Dr. Goldstein, without being thoroughly trained by a veterinarian.) In extreme cases, a constipated cat may not respond to dietary change or enemas, in which case the animal may have to be anesthetized for a procedure in which the veterinarian uses instruments to go into the colon and manually evacuate hardened feces.